1. Field of the Invention
The present invention relates to mortise locks and, in particular, to a high security and tamper proof visual indicator mounted on the outside of the door and in communication with the lock to indicate whether the door is locked or unlocked.
2. Description of Related Art
Mortise locksets generally include the mortise lock and inner and outer handle controllers or trim sets which operate the mortise lock. The mortise lock is mortised into the door and usually includes the latching mechanism which secures the door to the doorframe when the door is closed, as well as the locking mechanism which prevents the latching mechanism from being retracted when the door is locked.
The handle controllers are generally surface mounted on opposite sides of the door and have handles which operate the latching mechanism. In most current designs, the handle on each handle controller is directly connected to a shaft that extends into the mortise lock. The handle controllers also typically have some means of operating and controlling the lock mechanism in the mortise lock.
The outer surface of the door will have a key-operated lock cylinder having a tail that extends through the door skin and into the mortise lock through the surface of the door. Turning the key rotates the lock cylinder tail cam which operates the locking mechanism within the mortise lock to lock it and prevent the handle from being turned.
In mortise lock designs of this type, the lock cylinder (or similar mechanical or electrical lock device) will connect (via the lock cylinder tail cam) to a lock input on the mortise lock. The lock input connects to and operates the locking mechanism within the mortise lock. The shaft extending from the handle connects to a handle input on the mortise lock to retract the latch bolt in the mortise lock when the mortise lock is not locked.
Locking the mortise lock will normally block rotation of the handle input or associated linkages between the handle input and the latching mechanism. Locking will also normally extend the deadbolt. When the mortise lock mechanism is not locked, with the deadbolt retracted, rotation of the handle input will retract the latch bolt and allow the door to be opened.
The handle input and the lock input are normally operable from either face of the mortise lock. This allows the mortise lock to be installed in both left and right hand hinged doors. These inputs are engaged by corresponding shafts or members that extend out of the back of the handle controllers and through openings in the face of the door. The handle input is usually driven by the handle shaft and the lock input by the tail cam on the lock cylinder. This design also allows the inner handle controller to share the handle input with the outer handle controller so that either handle may operate the door.
An indicator on the outer surface of the door is known to show whether the door is locked (room occupied) or unlocked (room vacant). Such indicator locks are employed in hotel rooms and the guest may turn a thumb turn on the inside of the door to lock the door and to operate a signal mounted on the outer handle controller which shows whether the room is occupied or vacant. Such indicator products currently on the market, however, do not have the required security and can be easily tampered with or vandalized.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a mortise lock having a high security and tamper proof visual indicator which shows whether the door is locked or unlocked.
Another object of the invention is to employ a combination visual indicator module and lever handle/adapter module.
Other objects and advantages of the present invention will be apparent from the following description.